1. Field of the Invention
The present invention relates to a method and system for automatic selection of detour paths in a wireless mesh network.
2. Description of Related Art
Wireless Mesh Networks (WMNs) are two-tier networks where nomadic or mobile users access the Internet or intra-WMN services via a wireless backbone made of a number of Mesh Routers (MRs) communicating with each other over wireless links. The users can be laptops, cell phones, personal digital assistants, data collection devices and sensors (for example in the field of video-surveillance), and so on. MRs forward packets in a multi-hop manner to reach the intended destination within the WMN. Usually, MRs are in fixed positions, but some degree of mobility is also possible. Wireless mesh networks can be implemented with various technologies including 802.15, 802.11, 802.16 IEEE standards.
Even though nodes are usually in fixed positions, WMN resiliency is significantly affected by time-varying phenomena, like interference from co-located networks, shadowing, and obstruction, which are connected to the wireless channel characteristics. These phenomena may lead to transient wireless link failures that may occur at very short time scales.
Re-Routing techniques, that is techniques adapted to detour data packets into detour paths whenever a problem is detected on a primary path, are known in the art.
Re-Routing techniques can be of the reactive or proactive type. In the first case, detour paths are set-up a posteriori, whenever a failure is detected. In the second case, instead, detour paths are set-up a priori, before failure detection, in order to guarantee smaller response time.
For example, Fast Re-Routing (FRR) proactive techniques have been developed in the art to improve the resilience of wired (IP-based) networks. Multi Protocol Label Switching (MPLS) Fast Re-Route is standardized by the Internet Engineering Task Force (IETF) and is a feature of the RSVP Traffic Engineering (RSVP-TE) protocol. MPLS Fast Re-Route leverages on the availability of a Traffic Engineering Database (TED) containing detailed and up-to-date information of the network topology and resources reserved on each link. This information is usually collected by means of Open Shortest Path First routing protocol with Traffic Engineering extensions.